A bar code is a particular type of machine readable symbol, which includes parallel solid lines or bars of varying width and spacing. The alternating light and dark areas defined by the bars and the spaces between the bars represent a digital code which serves to identify the content of the bar code symbol. Labels bearing information in a number of different bar code formats are used in various applications, for example, to encode product identification information. Bar code labels are used on a broad range of retail packages for bar code reading and inventory purposes.
A bar code is read by a scanner, in which a beam of light is swept in a scan pattern to find and read a bar coda printed an a surface exposed to the scanner. A scanner may be located at the check-out station in a retail establishment to provide a clerk with a product identification information. A scanner of this type includes a laser sources, such as for example a gas discharge laser, which produces a laser beam pattern. The laser beam is directed to the surface of a bar code label and is swept across the surface by a motor-driven mirror assembly. The reflected light is sensed by a photosensitive element. Since light areas or spaces reflect more light than dark areas or bars, the reflected light intensity represents the digital code, which serves to identify the content of the bar code symbol. The digital code is decoded by a decoding system, which provides the product identification information.
While such an arrangement greatly enhances the efficiency of the check-out process difficulties are encountered in the scanning and decoding operations due to the number of different bar codes currently in use. For example, the scanning and decoding system must be capable of recognizing and decoding labels printed in one-dimensional bar codes as well as in two-dimensional bar codes. It is important that the system be capable of accomplishing this task automatically, without intervention by an operator, even when bar code labels having geometric pattern of different orientations are affined to products which are scanned.
In view of the above it would be desirable to provide a method of and apparatus for interfacing a bar code scanner and a bar code decode so as to automatically read a plurality of different one-dimensional and two-dimensional bar codes.